Насдедование

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
 
namespace Ui 
{
    class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private slots:
    void on_javaPathButton_clicked();
 
private:
    Ui::MainWindow *ui;
};
 
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "settings.h"
 
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_javaPathButton_clicked()
{
    settings Settings;
    ui->javaPathLine->setText(Settings.setJavaPath());
}

#ifndef SETTINGS_H
#define SETTINGS_H
 
#include <QFileDialog>
 
class settings
{
    public:
        QString setJavaPath();
};
 
#endif // SETTINGS_H

#include "settings.h"
 
QString settings::setJavaPath()
{
    QString javaPath = QFileDialog::getOpenFileName(this ,"Open File", "C:/", "java.exe");
    return (javaPath);
}

QString javaPath = QFileDialog::getOpenFileName(this ,"Open File", "C:/", "java.exe");

QString javaPath = QFileDialog::getOpenFileName(0 ,"Open File", "C:/", "java.exe");